/Engine/Source/Runtime/Engine/Public/Materials/MaterialRenderProxy.h
bool GetParameterValue ( EMaterialParameterType Type, const FHashedMaterialParameterInfo & ParameterInfo, [FMaterialParameterValue](API\Runtime\Engine\FMaterialParameterValue) & OutValue, const [FMaterialRenderContext](API\Runtime\Engine\FMaterialRenderContext) & Context ) const